ENPIRION EP5368QI

EP5368QI
600mA Synchronous Buck Regulator
With Integrated Inductor
3mm x 3mm x 1.1mm Package
April 2008
RoHS Compliant
Halogen Free
Product Overview
Featuring Integrated Inductor Technology
Product Highlights
• Integrated Inductor
• 3mm x 3mm x 1.1mm QFN package
• Only two low cost MLCC caps required
• 4 MHz switching frequency
• High efficiency, up to 94%
• Up to 700mA continuous output current
• Wide 2.4V to 5.5V input range
• VOUT Range 0.603V to VIN – 0.4V
• 100% duty cycle capable
• Less than 1 µA standby current
• Low VOUT ripple for RF compatibility
• Short circuit and over current protection
• UVLO and thermal protection
• Stable over entire operating range
• RoHS compliant; MSL 3 260°C reflow
Typical Application Circuit
VSense
ENABLE
VIN
Vin
4.7µF
0603
Voltage
Select
EP5368QI
VFB
VS0
V S1
VS2
VOUT
Vout
GND
Figure 1. Typical application circuit.
22µF
0805
The EP5368QI is a synchronous buck
converter with integrated Inductor, PWM
controller, MOSFETS, and Compensation
providing the smallest possible solution size.
The EP5368QI requires only two small MLCC
capacitors to make a complete solution.
Integration of the inductor greatly simplifies
design, contains noise, reduces part count, and
reduces solution footprint. Low output ripple
ensures compatibility with RF systems.
The EP5368QI operates at a switching
frequency
of
4
MHz,
enabling
this
unprecedented level of integration and small
external components. Type III voltage mode
control is used to provide high noise immunity
and wide control loop bandwidth. The device
is stable over all input and output voltages . It
can source 600mA of current over the
industrial temperature range and up to 700mA
over the commercial temperature range.
The small footprint makes this part ideal for
space constrained portable applications.
Shutdown current of <1uA extends battery life
Output voltage level is programmed via a 3-pin
VID selector providing seven pre-programmed
output voltages along with an option for
external resistor divider.
Applications
•
•
•
•
•
•
Noise sensitive RF applications
Area constrained applications
Smart phones and PDAs
Portable gaming devices
Personal Media Players
Advanced Mobile Processors, DSP, IO,
Memory, Video, Multimedia Engines
April 2008
EP5368QI
Pin Description
VSENSE (Pin 5): Sense pin for preset output
voltages. When using preset voltages connect
this to VLOAD or as close to VLOAD as possible to
ensure the best regulation. When using
external divider, connect this pin to VOUT.
AGND: (Pin 6):Analog ground. This is the
quiet ground for the internal control circuitry
VOUT (Pin 7,8): Regulated output voltage.
VS0,VS1,VS2 (Pin 10, 11, 12): Output voltage
select. VS2=pin10 VS1=pin11, VS0=pin12.
Selects one of seven preset output voltages or
choose external divider by connecting pins to
logic high or low. Logic low is defined as VLOW
≤ 0.4V. Logic high is defined as VHIGH ≥ 1.4V.
Any level between these two values is
indeterminate. (refer to section on output
voltage select for more detail).
Figure 2. EP5368QI Package Pin-out.
NC (Pins 1,3,9,15,16): These pins should not
be electrically connected to each other or to
any external signal, voltage, or ground. One or
more of these pins may be connected
internally.
ENABLE (Pin 13): Output enable. Enable =
logic high, disable = logic low. Logic low is
defined as VLOW ≤ 0.4V. Logic high is defined
as VHIGH ≥ 1.4V. Any level between these two
values is indeterminate.
PGND: (Pin 2): Power ground.
VFB (Pin 4): Feed back pin for external divider
option. When using the external divider option
(VS0=VS1=VS2= high) connect this pin to the
center of the external divider. Set the divider
such that VFB = 0.6V. The “ground” side of the
external divider should be connected to AGND.
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VIN (Pin 14): Input voltage pin. Supplies power
to the IC. VIN can range from 2.4V to 5.5V.
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April 2008
EP5368QI
Functional Block Diagram
VIN
UVLO
Thermal Limit
Current Limit
ENABLE
NC(SW)
Soft Start
P-Drive
(-)
Logic
VOUT
PWM
Comp
(+)
N-Drive
GND
VSENSE
Sawtooth
Generator
Compensation
Network
(-)
Switch
Error
Amp
VFB
(+)
DAC
Voltage
Select
VREF
Package Boundry
VS0 VS1 VS2
Figure 3. Functional block diagram.
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April 2008
EP5368QI
Absolute Maximum Ratings
CAUTION: Absolute Maximum ratings are stress ratings only. Functional operation beyond
recommended operating conditions is not implied. Stress beyond absolute maximum ratings may
cause permanent damage to the device. Exposure to absolute maximum rated conditions for
extended periods may affect device reliability.
PARAMETER
Input Supply Voltage
Voltages on: ENABLE, VSENSE, VS0-VS2
Voltage on: VFB
Storage Temperature Range
Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020C
ESD Rating (based on Human Body Model)
SYMBOL
MIN
MAX
UNITS
VIN
-0.3
-0.3
-0.3
-65
7.0
VIN + 0.3
2.7
150
260
2000
V
V
V
°C
°C
V
TSTG
Recommended Operating Conditions
PARAMETER
SYMBOL
MIN
MAX
UNITS
VIN
TA
TJ
2.4
-40
-40
5.5
+85
+125
V
Input Voltage Range
Operating Ambient Temperature
Operating Junction Temperature
°C
°C
Thermal Characteristics
PARAMETER
SYMBOL
TYP
UNITS
θJA
TJ-TP
100
+150
15
°C/W
°C
°C
Thermal Resistance: Junction to Ambient (0 LFM)
Thermal Overload Trip Point
Thermal Overload Trip Point Hysteresis
Electrical Characteristics
NOTE: TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C, VIN = 3.6V.
CIN = 4.7µF 0603 MLCC, COUT = 22uF 0805 MLCC.
PARAMETER
Operating Input Voltage
Output Voltage (presets)
SYMBOL
(VS pins must not be left floating)
Vo
Output Voltage
(external divider)
Dynamic Voltage Slew Rate
Continuous Output Current
TEST CONDITIONS
VIN
MIN
2.4
0.6
IOUT
Shut-Down Current
PFET OCP Threshold
ISD
ILIM
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VIN = 5V, 0.603V <VOUT < 3.3V
TA = -40°C to +85°C
VIN = 5V, 0.603V <VOUT < 3.3V
TA = -10°C to +85°C;
(Application Circuit Figure 5.)
Enable = Low
2.4V ≤ VIN ≤ 5.5V, 0.6V ≤ VIN ≤ 3.3V
4
UNITS
V
V
VIN-0.4
1.5
Vslew
Continuous Output Current
MAX
5.5
Vout
3.3
2.5
1.8
1.5
1.25
1.2
0.8
ext.
VS2 VS1 VS0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Vo
IOUT
TYP
V
mV/µS
600
mA
700
mA
1.4
0.75
2
µA
A
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April 2008
EP5368QI
PARAMETER
Feedback Pin Voltage
Feedback Pin Input Current
VS0-VS1, Enable Voltage
Threshold
VS0-VS2 Pin Input Current
Operating Frequency
PFET On Resistance
NFET On Resistance
VOUT Accuracy
SYMBOL
TEST CONDITIONS
MIN
VFB
IFB
VTH
Pin = Low
Pin = High
Line Regulation
Load Regulation
Soft-Start Operation
Soft-Start Slew Rate
Time to 90% Vout
Vss
Tss
MAX
100
0.4
VIN
0.0
1.4
IVSX
FOSC
RDS(ON)
RDS(ON)
VOUT
TYP
0.603
1
4
340
270
TA = 25°C 2.4V ≤ VIN ≤ 5.5V
-40°C ≤ TA ≤ +85°CV (all causes)
2.4V ≤ VIN ≤ 5.5V
0A ≤ ILOAD ≤ 700mA
Vout = 3.3V
-2%
-3%
UNITS
V
nA
nA
MHz
mΩ
mΩ
+2%
+3%
0.0566
0.0003
%/V
%/ mA
1.5
2.2
mV/µS
mS
100
100
95
95
90
90
85
85
Efficiency (%)
Efficiency (%)
Typical Performance Characteristics
80
75
70
80
75
70
65
65
60
60
55
55
50
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
50
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
Load Current (A)
Load Current (A)
Efficiency, VIN = 3.3V, VOUT = 1.2V, 1.5V,1.8V, 2.5V
Efficiency, VIN = 3.7V, VOUT = 1.2V, 1.5V,1.8V, 2.5V
100
95
90
Efficiency (%)
85
80
75
70
65
60
55
50
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
Load Current (A)
Efficiency, VIN = 5V, VOUT = 1.2V, 1.5V,1.8V, 2.5V, 3.3V
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Transient, VIN = 3.6V, VOUT = 1.2V, Load = 0-500mA
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April 2008
EP5368QI
Startup, VIN = 3.6V, VOUT = 1.5V, Load = 500mA
Shutdown, VIN = 3.6V, VOUT = 1.5V, Load = 500mA
Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 0mA
COUT = 1x 22uF 0805, 2.0mV/Div.
Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 600mA
COUT = 1x 22uF 0805, 2.0mV/Div.
Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 0mA
COUT = 2x 10uF 0805, 2.0mV/Div.
Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 600mA
COUT = 2x 10uF 0805, 2.0mV/Div.
Detailed Description
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EP5368QI
Integrated Inductor
Functional Overview
Enpirion has introduced the world’s first
product family featuring integrated inductors.
The EP5368QI utilizes a proprietary low loss
integrated inductor. The use of an internal
inductor localizes the noises associated with
the output loop currents. The inherent shielding
and compact construction of the integrated
inductor reduces the radiated noise that
couples into the traces of the circuit board.
Further, the package layout is optimized to
reduce the electrical path length for the AC
ripple currents that are a major source of
radiated emissions from DCDC converters.
The integrated inductor significantly reduces
parasitic effects that can harm loop stability,
and makes layout very simple.
The EP5368QI is a complete DCDC converter
solution requiring only two low cost MLCC
capacitors.
MOSFET switches, PWM
controller, Gate-drive, compensation, and
inductor are integrated into the tiny 3mm x
3mm x 1.1mm package to provide the smallest
footprint possible while maintaining high
efficiency, low ripple, and high performance.
The converter uses voltage mode control to
provide the simplest implementation and high
noise immunity. The device operates at a
4MHz switching frequency. The high switching
frequency allows for a wide control loop
bandwidth
providing
excellent
transient
performance. The high switching frequency
further enables the use of very small
components
making
possible
this
unprecedented level of integration.
Stable Over Wide Range of Operating
Conditions
Enpirion’s
proprietary
power
MOSFET
technology provides very low switching loss at
frequencies of 4 MHz and higher, allowing for
the use of very small internal components, and
high performance. Integration of the magnetics
virtually eliminates the design/layout issues
normally associated with switch-mode DCDC
converters. All of this enables much easier
and
faster
incorporation
into
various
applications to meet demanding EMI
requirements.
The EP5368QI utilizes an internal type III
compensation network and is designed to
provide a high degree of stability over a wide
range of operating conditions. The device
operates over the entire input and output
voltage range with no external modifications
required. The very high switching frequency
allows for a very wide control loop bandwidth.
Soft Start
Internal soft start circuits limit in-rush current
when the device starts up from a power down
condition or when the “ENABLE” pin is
asserted “high”. Digital control circuitry limits
the VOUT ramp rate to levels that are safe for
the Power MOSFETS and the integrated
inductor. The soft start ramp rate is nominally
1.5V/mS.
Output voltage is chosen from seven preset
values via a three pin VID voltage select
scheme. An external divider option enables
the selection of any voltage in VIN to 0.6V
range. This reduces the number of
components that must be qualified and
reduces inventory burden. The VID pins can
be toggled on the fly to implement glitch free
dynamic voltage scaling.
Protection features include under-voltage lockout (UVLO), over-current protection (OCP),
short circuit protection, and thermal overload
protection.
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April 2008
EP5368QI
Over Current/Short Circuit Protection
Enable
The current limit function is achieved by
sensing the current flowing through a sense PMOSFET which is compared to a reference
current. When this level is exceeded the PFET is turned off and the N-FET is turned on,
pulling VOUT low. This condition is maintained
for a period of 1mS and then a normal soft start
is initiated. If the over current condition still
persists, this cycle will repeat in a “hiccup”
mode.
The ENABLE pin provides a means to shut
down the converter or enable normal
operation. A logic low will disable the converter
and cause it to shut down. A logic high will
enable the converter into normal operation. In
shutdown mode, the device quiescent current
will be less than 1 uA.
NOTE: This pin must not be left floating.
Thermal Shutdown
Under Voltage Lockout
When excessive power is dissipated in the
chip, the junction temperature rises. Once the
junction temperature exceeds the thermal
shutdown temperature the thermal shutdown
circuit turns off the converter output voltage
thus allowing the device to cool. When the
junction temperature decreases by 15C°, the
device will go through the normal startup
process.
During initial power up an under voltage
lockout circuit will hold-off the switching
circuitry until the input voltage reaches a
sufficient level to insure proper operation. If
the voltage drops below the UVLO threshold
the lockout circuitry will again disable the
switching. Hysteresis is included to prevent
chattering between states.
Application Information
hardwired to VIN or GND or alternatively can be
driven by standard logic levels. Logic low is
defined as VLOW ≤ 0.4V. Logic high is defined
as VHIGH ≥ 1.4V. Any level between these two
values is indeterminate. These pins must not
be left floating.
Output Voltage Select
To provide the highest degree of flexibility in
choosing output voltage, the EP5368QI uses a
3 pin VID, or Voltage ID, output voltage select
arrangement. This allows the designer to
choose one of seven preset voltages, or to use
an external voltage divider. Internally, the
output of the VID multiplexer sets the value for
the voltage reference DAC, which in turn is
connected to the non-inverting input of the
error amplifier. This allows the use of a single
feedback divider with constant loop gain and
optimum compensation, independent of the
output voltage selected.
Table 1. VID voltage select settings.
VS2
0
0
0
0
1
1
1
1
Table 1 shows the various VS0-VS2 pin logic
states and the associated output voltage
levels. A logic “1” indicates a connection to VIN
or to a “high” logic voltage level. A logic “0”
indicates a connection to ground or to a “low”
logic voltage level. These pins can be either
©Enpirion 2008 all rights reserved, E&OE
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VS1
0
0
1
1
0
0
1
1
VS0
0
1
0
1
0
1
0
1
VOUT
3.3V
2.5V
1.8V
1.5V
1.25V
1.2V
0.8V
User
Selectable
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April 2008
EP5368QI
External Voltage Divider
Input and Output Capacitors
As described above, the external voltage
divider option is chosen by connecting the
VS0, VS1, and VS2 pins to VIN or logic “high”.
The EP5368QI uses a separate feedback pin,
VFB, when using the external divider. VSENSE
must be connected to VOUT as indicated in
Figure 4.
VSense
ENABLE
VIN
Vin
4.7uF
0603
The input capacitance requirement is 4.7uF
0603 MLCC. The input capacitor must be a
X5R/X7R MLCC. Y5V or equivalent dielectric
formulations lose capacitance with frequency,
bias, and with temperature, and are not
suitable for switch-mode DC-DC converter
input filter applications.
VOUT
Vout
Ra
EP5368QI
The output capacitance requirement is
approximately 20uF. Enpirion recommends a
single 22uF 0805 MLCC. Ripple performance
can be improved by using 2 x 10uF 0805 MLC
capacitors.
22µF
0805
VFB
VS0
VS1
Rb
VS2
GND
The output capacitor must be a X5R/X7R or
equivalent MLCC. Y5V or equivalent dielectric
formulations lose capacitance with frequency,
bias, and temperature and are not suitable for
switch-mode DC-DC converter output filter
applications.
Figure 4. External Divider application circuit.
The output voltage is selected by the following
formula:
VOUT = 0.603V (1 +
Ra
Rb
)
Please consult Enpirion Applications Support
for other capacitor case size combinations.
Ra must be chosen as 200KΩ to maintain loop
gain. Then Rb is given as:
Rb =
1.206 x10 5
Ω
VOUT − 0.603
Operation at 700mA Output Current
VOUT can be programmed over the range of
0.603V to VIN-0.4V.
Operation at 700mA is supported by using the
application circuit shown in Figure 5. The
modification in the compensation is to ensure
stability over the entire set of input and output
voltage conditions.
Dynamically Adjustable Output
The EP5368QI is designed to allow for
dynamic switching between the predefined VID
voltage levels The inter-voltage slew rate is
optimized to prevent excess undershoot or
overshoot as the output voltage levels
transition. The slew rate is identical to the softstart slew rate of 1.5V/mS.
VSense
ENABLE
VIN
Vin
4.7uF
0603
Ca
22µF
0805
VFB
VS0
VS1
Dynamic transitioning between internal VID
settings and the external divider is not allowed.
Ra
EP5368QI
VS2
VOUT
Vout
Rb
GND
Figure 5. Applications circuit for operation at 700mA.
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April 2008
EP5368QI
For 700mA operation, use the following
component values:
VOUT can be programmed over the range of
0.603V to VIN-0.4V.
Ra = 249KΩ.
Ca = 15pF 0402 MLCC capacitor.
Stability cannot be assured if these guidelines
are not followed.
Then Rb is given as:
Rb =
1.501x10 5
Ω
VOUT − 0.603
Recommended PCB Footprint
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EP5368QI
Package Dimensions
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April 2008
EP5368QI
Contact Information
Enpirion, Inc.
685 US Route 202/206 Suite 305
Bridgewater, NJ 08807
Phone: +1 908-575-7550
Fax: +1 908-575-0775
Enpirion reserves the right to make changes in circuit design and/or specifications at any time without notice. Information furnished by Enpirion is
believed to be accurate and reliable. Enpirion assumes no responsibility for its use or for infringement of patents or other third party rights, which may
result from its use. Enpirion products are not authorized for use in nuclear control systems, as critical components in life support systems or equipment
used in hazardous environment without the express written authority from Enpirion.
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